textproduct: Quad Cities

KEY MESSAGES

- A dense fog advisory is in effect for the entire area this morning. Patchy drizzle is also possible.

- Rain possible late Thursday night through Monday.

- Well above normal temperatures are forecast today through Monday. Temperatures will cool on Tuesday and Wednesday.

SHORT TERM /THROUGH FRIDAY/

Issued at 222 AM CST Thu Dec 26 2024

At 2 AM, temperatures and dewpoints range from the lower 30s to lower 40s from north to south with relative humidities around 100 percent. There is widespread dense fog across eastern Iowa, northwest Illinois and far northeast Missouri. Radar does show patchy drizzle lifting northward across the area.

Some uncertainty in the forecast through the day as dense fog may last longer than forecast with no mechanism to scour out the moisture below the inversion. Forecast soundings across the CWA show weakening in the strength of the inversion across the CWA as well as some drying of the sounding with time. Decided to expand the Dense Fog Advisory across the remainder of the CWA through 11 AM. The Dense Fog Advisory along and south of a Fairfield to Galesburg line expires at 9 AM. We will continue to monitor observation trends across the area and the Dense Fog Advisory may need to be expanded in time. We do expect improvement in visibilities as we go through the day with drizzle continuing to occur. Given the dense fog and cloud cover, decided to cool high temperatures slightly for today with high temperatures ranging from around 40 degrees along the Highway 20 corridor to the upper 40s in far southeast Iowa, far northeast Missouri and west central Illinois.

A storm system moving across the southern Plains is forecast to lift northeast after 00 UTC on Friday and into northern Illinois by 00 UTC Saturday. As this occurs, moisture depth in the atmosphere will increase significantly with widespread rain developing after midnight and continuing through the day on Friday. Due to the widespread rain decided to lower high temperatures for Friday. High temperatures on Friday are in the mid to upper 40s. Rainfall amounts through Friday are 0.20 to 0.30 across the area with the highest amounts in far northeast Missouri and west central Illinois.

LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/

Issued at 222 AM CST Thu Dec 26 2024

West to east zonal flow continues across the US with several shortwaves moving across the Plains. This will result in daily chances of rain Friday night through Monday. This period will not be a complete washout but there will be dry periods as high pressure moves across the area in the wake of each system. Thermal profiles through the period support precipitation falling as all rain. Saturday looks to be the warmest day of the period with high temperatures in the upper 40s to lower 50s. Temperatures cool by a couple of degrees on Sunday and Monday.

Tuesday through the end of the period a closed upper level low is forecast to dig southward from southern Canada into the Upper Great Lakes. As this occurs, surface low pressure will move across the area and bring a cold front across the area late Monday into Tuesday. There is some disagreement on the track of this storm system with the GFS bring the surface low along the Iowa Missouri while the ECMWf brings it across southern Missouri. Given the different tracks and their potential impacts on precipitation type have continued to use a rain and snow mix Monday night into Tuesday. The current forecast has high temperatures on Monday and Tuesday in the 30s.

On Wednesday,New Years Day, high pressure is forecast to move southward into the Plains with quiet weather. High temperatures will be in the lower to mid 30s.

AVIATION /06Z TAFS THROUGH 06Z FRIDAY/

Issued at 1036 PM CST Wed Dec 25 2024

Rather sloppy aviation conditions are expected late this evening through the day Thursday as increasing low-level moisture will support widespread LIFR/VLIFR ceilings and visibilities due to fog, as well as some patchy drizzle. There continues to be a bit more uncertainty on whether or not MLI and BRL fall to 1/4SM visby tonight, given high-res model probabilities of less than 1/2SM visby of 40 percent or less. Some VLIFR conditions should linger through the TAF period for CID and DBQ, but conditions should improve late in the day as drier air filters in from the southeast, eventually scouring out any fog and low stratus.

DVN WATCHES/WARNINGS/ADVISORIES

IA...Dense Fog Advisory until 11 AM CST this morning for IAZ040>042- 051>054-063>068-076>078. Dense Fog Advisory until 9 AM CST this morning for IAZ087>089- 098-099. IL...Dense Fog Advisory until 11 AM CST this morning for ILZ001-002- 007-009-015>018-024. Dense Fog Advisory until 9 AM CST this morning for ILZ025-026- 034-035. MO...Dense Fog Advisory until 9 AM CST this morning for MOZ009-010.